State the principle of working of a cyclotron. Describe the construction with a neat labelled diagram.

Explanation

principle of working : The cyclotron uses the principle of synschronous acceleration to accerlerate charged particles which describe a spiral path at right angles to a constant magnetic field and make multiple passes through the same alternating p.D., whose frequency is the same as the frequency of revolution of the particles.
Construction of the cyclotron : Two hollow D-shaped chambers that are open at their straight edges form the electrodes. They are called the dees. The dees are separated by a small gap, a shown in the figure, and a high-frequency `(10^(6) "Hz to" 10^(7) "Hz")` alternating p.d. ( of the order of `10^(4)V` to `10^(5)V` ) is applied between them. The whole system is placed in an evacuated chamber between the poles of large and strong electromagnet of strength 1 T to 2 T .

The ions to be accelerated are producd in an ion source, a hydrogen tube gives protons, heavy hydrogen or deutreium gives near the centre and are accerlerated each time theyc cross the gap between the dees. At the edge of one of the dees, and electrostatic deflector at negative potential deflects the spiralling particles out of the system to strike a target.